The present invention relates generally to pavement marking, and more particularly to a handle/actuator assembly for a thermoplastic die box.
Alkyd and hydrocarbon thermoplastics are commonly used to mark pavement surfaces with visible lines and symbols such as lane dividers and guide lines. In particular, thermoplastics provide a durable alternative to pavement painting, and are commonly used to mark street intersections, parking lots, and other high-traffic pavement surfaces from which paint would quickly wear away.
Thermoplastics are conventionally applied to pavement surfaces using a mobile applicator comprising a heated reservoir or kettle, and an application screed die. Melted thermoplastic is dispensed from the kettle at a controlled rate and applied in a thin layer atop pavement surfaces with the screed die. Some applicators further comprise secondary burners, which heat secondary reservoirs or the screed die.
In general, governmental regulations determine width or pattern of lines and marks on street intersections and parking lots. In order to achieve lines or patterns of varying widths, the appropriately sized screed die box must be used with a gate valve set to the appropriate height from the surface. Generally, screed die boxes are available in sizes ranging from 4-12 inches in width. A gate valve height can be preset such that a handle or lever is used only to open and close the screed die box during operation. Screed die boxes are regularly interchanged at the application site, where a user is limited by time constraints and the absence of mechanical facilities for storage and disassembly/reassembly. Handles welded or securely bolted to the screed die box are designed to control the gate valve and to support the heavy screed die box when used to lift the screed die box off of the mobile applicator and move the screed die box off-site. Handles of unitary construction with the screed die box require significant storage space; whereas handles bolted to the screed die box require tools for disassembly/reassembly that must be stored and transported to job sites.
A need exists for a quick disconnect handle assembly capable of supporting the weight of a full screed die box when lifted, withstanding the force applied at the connection point of the handle and screed die box in opening and closing the gate valve, and remaining securely fastened without risk of accidental disconnection from the screed die box during operation.